hush: rework signal and trap handling. Some smaller bits are TODO,
expect minor breakage
function old new delta
set_fatal_sighandler 12 186 +174
check_and_run_traps - 122 +122
maybe_set_sighandler - 76 +76
hush_main 831 887 +56
sigtimedwait - 50 +50
__GI_sigtimedwait - 50 +50
hush_exit 49 93 +44
set_mode 749 777 +28
pseudo_exec_argv 131 151 +20
static.zero_ts - 8 +8
expand_variables 1962 1970 +8
builtin_wait 172 174 +2
set_misc_sighandler 12 - -12
set_jobctrl_sighandler 12 - -12
handler_ctrl_c 16 - -16
builtin_set_mode 28 - -28
handle_trap 97 - -97
handler_ctrl_z 107 - -107
builtin_trap 545 438 -107
run_list 2149 2006 -143
------------------------------------------------------------------------------
(add/remove: 5/6 grow/shrink: 7/2 up/down: 638/-522) Total: 116 bytes
diff --git a/shell/hush.c b/shell/hush.c
index cd6e12b..bcccfb0 100644
--- a/shell/hush.c
+++ b/shell/hush.c
@@ -460,13 +460,13 @@
int last_jobid;
struct pipe *job_list;
struct pipe *toplevel_list;
- smallint ctrl_z_flag;
+//// smallint ctrl_z_flag;
#endif
#if ENABLE_HUSH_LOOPS
smallint flag_break_continue;
#endif
smallint fake_mode;
- /* these three support $?, $#, and $1 */
+ /* These four support $?, $#, and $1 */
smalluint last_return_code;
/* is global_argv and global_argv[1..n] malloced? (note: not [0]) */
smalluint global_args_malloced;
@@ -489,10 +489,14 @@
#endif
unsigned char charmap[256];
char user_input_buf[ENABLE_FEATURE_EDITING ? BUFSIZ : 2];
- struct {
- char *cmd;
- struct sigaction oact;
- } *traps;
+ /* Signal and trap handling */
+ char **traps; /* char *traps[NSIG] */
+ /* which signals have non-DFL handler (even with no traps set)? */
+ unsigned non_DFL_mask;
+ /* which signals are known to be IGNed on entry to shell? */
+ unsigned IGN_mask;
+ sigset_t blocked_set;
+ sigset_t inherited_set;
};
#define G (*ptr_to_globals)
@@ -521,11 +525,9 @@
static int builtin_pwd(char **argv);
static int builtin_read(char **argv);
static int builtin_test(char **argv);
-static void handle_trap(int sig);
static int builtin_trap(char **argv);
static int builtin_true(char **argv);
static int builtin_set(char **argv);
-static int builtin_set_mode(const char, const char);
static int builtin_shift(char **argv);
static int builtin_source(char **argv);
static int builtin_umask(char **argv);
@@ -750,95 +752,270 @@
}
-/* Signals are grouped, we handle them in batches */
-static void set_misc_sighandler(void (*handler)(int))
+/* Basic theory of signal handling in shell
+ * ========================================
+ * This does not describe what hush does, rahter, it is current understanding
+ * what it _should_ do.
+ * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
+ *
+ * Signals are handled only after each pipe ("cmd | cmd | cmd" thing)
+ * is finished or backgrounded. It is the same in interactive and
+ * non-interactive shells, and is the same regardless of whether
+ * a user trap handler is installed or a default one is in effect.
+ * ^C or ^Z from keyboard seem to execute "at once" because it usually
+ * backgrounds (i.e. stops) or kills all members of currently running
+ * pipe.
+ *
+ * Wait builtin in interruptible by signals for which user trap is set
+ * or by SIGINT in interactive shell.
+ *
+ * Trap handlers will execute even within trap handlers. (right?)
+ *
+ * User trap handlers are forgotten when subshell is entered.
+ *
+ * If job control is off, backgrounded commands ("cmd &")
+ * have SIGINT, SIGQUIT set to SIG_IGN.
+ *
+ * Commands run in command substitution ("`cmd`")
+ * have SIGTTIN, SIGTTOU, SIGTSTP set to SIG_IGN.
+ *
+ * Ordinary commands have IGN/DFL set as inherited by the shell
+ * from its parent.
+ *
+ * Default handlers which differ from DFL action
+ * (note: subshell is not an interactive shell):
+ *
+ * SIGQUIT: ignore
+ * SIGTERM (interactive): ignore
+ * SUGHUP (interactive): send SIGCONT to stopped jobs,
+ * send SIGHUP to all jobs and exit
+ * SIGTTIN, SIGTTOU, SIGTSTP (if job control is on): ignore
+ * (note that ^Z is handled not by trapping SIGTSTP, but by seeing
+ * that all pipe members are stopped) (right?)
+ * SIGINT (interactive): wait for last pipe, ignore the rest
+ * of the command line, show prompt. (check/expand this)
+ * Example 1: this waits 5 sec, but does not execute ls:
+ * "echo $$; sleep 5; ls -l" + "kill -INT <pid>"
+ * Example 2: this does not wait and does not execute ls:
+ * "echo $$; sleep 5 & wait; ls -l" + "kill -INT <pid>"
+ *
+ * (What happens to signals which are IGN on shell start?)
+ * (What happens with signal mask on shell start?)
+ *
+ * Implementation in hush
+ * ======================
+ * We use in-kernel pending signal mask to determine which signals were sent.
+ * We block all signals which we don't want to take action immediately,
+ * i.e. we block all signals which need to have special handling as described
+ * above, and all signals which have traps set.
+ * After each pipe execution, we extract any pending signals via sigtimedwait()
+ * and act on them.
+ *
+ * unsigned non_DFL_mask: a mask of such "special" signals
+ * sigset_t blocked_set: current blocked signal set
+ *
+ * "trap - SIGxxx": clear bit in blocked_set unless it is also in non_DFL
+ * "trap 'cmd' SIGxxx": set bit in blocked_set (even if 'cmd' is '')
+ * after [v]fork, if we plan to be a shell:
+ * nothing for {} subshell (say, "true | { true; true; } | true")
+ * unset all traps if () shell. [TODO]
+ * after [v]fork, if we plan to exec:
+ * POSIX says pending signal mask is cleared in child - no need to clear it.
+ * restore blocked signal set to one inherited by shell just prior to exec.
+ *
+ * Note: as a result, we do not use signal handlers much. The only use
+ * is to restore terminal pgrp on exit.
+ *
+ * TODO: check/fix wait builtin to be interruptible.
+ */
+
+/* called once at shell init */
+static void init_signal_mask(void)
{
- bb_signals(0
- + (1 << SIGINT)
- + (1 << SIGQUIT)
- + (1 << SIGTERM)
- , handler);
+ unsigned sig;
+ unsigned mask = (1 << SIGQUIT);
+#if ENABLE_HUSH_INTERACTIVE
+ if (G.interactive_fd) {
+ mask = 0
+ | (1 << SIGQUIT)
+ | (1 << SIGTERM)
+ | (1 << SIGHUP)
+#if ENABLE_HUSH_JOB
+ | (1 << SIGTTIN) | (1 << SIGTTOU) | (1 << SIGTSTP)
+#endif
+ | (1 << SIGINT)
+ ;
+ }
+#endif
+ G.non_DFL_mask = mask;
+
+ /*sigemptyset(&G.blocked_set); - already is */
+ sigprocmask(SIG_SETMASK, NULL, &G.blocked_set);
+ sig = 0;
+ while (mask) {
+ if (mask & 1)
+ sigaddset(&G.blocked_set, sig);
+ mask >>= 1;
+ sig++;
+ }
+ sigprocmask(SIG_SETMASK, &G.blocked_set, &G.inherited_set);
}
+static void check_and_run_traps(void)
+{
+ static const struct timespec zero_ts = { 0, 0 };
+ smalluint save_rcode;
+ int sig;
+
+ while (1) {
+ sig = sigtimedwait(&G.blocked_set, NULL, &zero_ts);
+ if (sig <= 0)
+ break;
+
+ if (G.traps && G.traps[sig]) {
+ if (G.traps[sig][0]) {
+ /* We have user-defined handler */
+ char *argv[] = { NULL, xstrdup(G.traps[sig]), NULL };
+ save_rcode = G.last_return_code;
+ builtin_eval(argv);
+ free(argv[1]);
+ G.last_return_code = save_rcode;
+ } /* else: "" trap, ignoring signal */
+ continue;
+ }
+ /* not a trap: special action */
+#if 0 //TODO
+ switch (sig) {
+ case SIGHUP: ...
+ break;
+ case SIGINT: ...
+ break;
+ default: /* SIGTERM, SIGQUIT, SIGTTIN, SIGTTOU, SIGTSTP */
+ }
+#endif
+ }
+}
+
+/* The stuff below needs to be migrated to "Special action" above */
+
+/////* Signals are grouped, we handle them in batches */
+////static void set_misc_sighandler(void (*handler)(int))
+////{
+//// bb_signals(0
+//// + (1 << SIGINT)
+//// + (1 << SIGQUIT)
+//// + (1 << SIGTERM)
+//// , handler);
+////}
#if ENABLE_HUSH_JOB
+/* helper */
+static unsigned maybe_set_sighandler(int sig, void (*handler)(int))
+{
+ /* non_DFL_mask'ed signals are, well, masked,
+ * no need to set handler for them.
+ * IGN_mask'ed signals were found to be IGN on entry,
+ * do not change that -> no need to set handler for them either
+ */
+ unsigned ign = ((G.IGN_mask|G.non_DFL_mask) >> sig) & 1;
+ if (!ign) {
+ handler = signal(sig, handler);
+ ign = (handler == SIG_IGN);
+ if (ign) /* restore back to IGN! */
+ signal(sig, handler);
+ }
+ return ign << sig; /* pass back knowledge about SIG_IGN */
+}
+/* Used only to set handler to restore pgrp on exit, and to reset it to DFL */
static void set_fatal_sighandler(void (*handler)(int))
{
- bb_signals(0
- + (1 << SIGILL)
- + (1 << SIGTRAP)
- + (1 << SIGABRT)
- + (1 << SIGFPE)
- + (1 << SIGBUS)
- + (1 << SIGSEGV)
+ unsigned mask = 0;
+
+ if (HUSH_DEBUG) {
+ mask |= maybe_set_sighandler(SIGILL , handler);
+ mask |= maybe_set_sighandler(SIGFPE , handler);
+ mask |= maybe_set_sighandler(SIGBUS , handler);
+ mask |= maybe_set_sighandler(SIGSEGV, handler);
+ mask |= maybe_set_sighandler(SIGTRAP, handler);
+ } /* else: hush is perfect. what SEGV? */
+
+ mask |= maybe_set_sighandler(SIGABRT, handler);
+
/* bash 3.2 seems to handle these just like 'fatal' ones */
- + (1 << SIGHUP)
- + (1 << SIGPIPE)
- + (1 << SIGALRM)
- , handler);
+ mask |= maybe_set_sighandler(SIGPIPE, handler);
+ mask |= maybe_set_sighandler(SIGALRM, handler);
+ mask |= maybe_set_sighandler(SIGHUP , handler);
+
+ /* if we aren't interactive... but in this case
+ * we never want to restore pgrp on exit, and this fn is not called */
+ /*mask |= maybe_set_sighandler(SIGTERM, handler); */
+ /*mask |= maybe_set_sighandler(SIGINT , handler); */
+
+ G.IGN_mask = mask;
}
-static void set_jobctrl_sighandler(void (*handler)(int))
+/* Used only to suppress ^Z in `cmd` */
+static void IGN_jobctrl_signals(void)
{
bb_signals(0
+ (1 << SIGTSTP)
+ (1 << SIGTTIN)
+ (1 << SIGTTOU)
- , handler);
+ , SIG_IGN);
}
/* SIGCHLD is special and handled separately */
-static void set_every_sighandler(void (*handler)(int))
-{
- set_fatal_sighandler(handler);
- set_jobctrl_sighandler(handler);
- set_misc_sighandler(handler);
- signal(SIGCHLD, handler);
-}
+////static void set_every_sighandler(void (*handler)(int))
+////{
+//// set_fatal_sighandler(handler);
+//// set_jobctrl_sighandler(handler);
+//// set_misc_sighandler(handler);
+//// signal(SIGCHLD, handler);
+////}
-static void handler_ctrl_c(int sig UNUSED_PARAM)
-{
- debug_printf_jobs("got sig %d\n", sig);
-// as usual we can have all kinds of nasty problems with leaked malloc data here
- siglongjmp(G.toplevel_jb, 1);
-}
+////static void handler_ctrl_c(int sig UNUSED_PARAM)
+////{
+//// debug_printf_jobs("got sig %d\n", sig);
+////// as usual we can have all kinds of nasty problems with leaked malloc data here
+//// siglongjmp(G.toplevel_jb, 1);
+////}
-static void handler_ctrl_z(int sig UNUSED_PARAM)
-{
- pid_t pid;
-
- debug_printf_jobs("got tty sig %d in pid %d\n", sig, getpid());
-
- if (!BB_MMU) {
- fputs("Sorry, backgrounding (CTRL+Z) of foreground scripts not supported on nommu\n", stderr);
- return;
- }
-
- pid = fork();
- if (pid < 0) /* can't fork. Pretend there was no ctrl-Z */
- return;
- G.ctrl_z_flag = 1;
- if (!pid) { /* child */
- if (ENABLE_HUSH_JOB)
- die_sleep = 0; /* let nofork's xfuncs die */
- bb_setpgrp();
- debug_printf_jobs("set pgrp for child %d ok\n", getpid());
- set_every_sighandler(SIG_DFL);
- raise(SIGTSTP); /* resend TSTP so that child will be stopped */
- debug_printf_jobs("returning in child\n");
- /* return to nofork, it will eventually exit now,
- * not return back to shell */
- return;
- }
- /* parent */
- /* finish filling up pipe info */
- G.toplevel_list->pgrp = pid; /* child is in its own pgrp */
- G.toplevel_list->cmds[0].pid = pid;
- /* parent needs to longjmp out of running nofork.
- * we will "return" exitcode 0, with child put in background */
-// as usual we can have all kinds of nasty problems with leaked malloc data here
- debug_printf_jobs("siglongjmp in parent\n");
- siglongjmp(G.toplevel_jb, 1);
-}
+////static void handler_ctrl_z(int sig UNUSED_PARAM)
+////{
+//// pid_t pid;
+////
+//// debug_printf_jobs("got tty sig %d in pid %d\n", sig, getpid());
+////
+//// if (!BB_MMU) {
+//// fputs("Sorry, backgrounding (CTRL+Z) of foreground scripts not supported on nommu\n", stderr);
+//// return;
+//// }
+////
+//// pid = fork();
+//// if (pid < 0) /* can't fork. Pretend there was no ctrl-Z */
+//// return;
+//// G.ctrl_z_flag = 1;
+//// if (!pid) { /* child */
+//// if (ENABLE_HUSH_JOB)
+//// die_sleep = 0; /* let nofork's xfuncs die */
+//// bb_setpgrp();
+//// debug_printf_jobs("set pgrp for child %d ok\n", getpid());
+//////// set_every_sighandler(SIG_DFL);
+//// raise(SIGTSTP); /* resend TSTP so that child will be stopped */
+//// debug_printf_jobs("returning in child\n");
+//// /* return to nofork, it will eventually exit now,
+//// * not return back to shell */
+//// return;
+//// }
+//// /* parent */
+//// /* finish filling up pipe info */
+//// G.toplevel_list->pgrp = pid; /* child is in its own pgrp */
+//// G.toplevel_list->cmds[0].pid = pid;
+//// /* parent needs to longjmp out of running nofork.
+//// * we will "return" exitcode 0, with child put in background */
+////// as usual we can have all kinds of nasty problems with leaked malloc data here
+//// debug_printf_jobs("siglongjmp in parent\n");
+//// siglongjmp(G.toplevel_jb, 1);
+////}
/* Restores tty foreground process group, and exits.
* May be called as signal handler for fatal signal
@@ -865,8 +1042,8 @@
#else /* !JOB */
-#define set_fatal_sighandler(handler) ((void)0)
-#define set_jobctrl_sighandler(handler) ((void)0)
+#define set_fatal_sighandler(handler) ((void)0)
+#define IGN_jobctrl_signals(handler) ((void)0)
#endif /* JOB */
@@ -874,8 +1051,11 @@
static void hush_exit(int exitcode) NORETURN;
static void hush_exit(int exitcode)
{
- if (G.traps && G.traps[0].cmd)
- handle_trap(0);
+ if (G.traps && G.traps[0] && G.traps[0][0]) {
+ char *argv[] = { NULL, xstrdup(G.traps[0]), NULL };
+ builtin_eval(argv);
+ free(argv[1]);
+ }
if (ENABLE_HUSH_JOB) {
fflush(NULL); /* flush all streams */
@@ -2052,6 +2232,8 @@
}
#endif
+ sigprocmask(SIG_SETMASK, &G.inherited_set, NULL);
+
debug_printf_exec("execing '%s'\n", argv[0]);
execvp(argv[0], argv);
bb_perror_msg("can't exec '%s'", argv[0]);
@@ -2200,6 +2382,8 @@
pid_t childpid;
int rcode = 0;
+ debug_printf_jobs("checkjobs %p\n", fg_pipe);
+
attributes = WUNTRACED;
if (fg_pipe == NULL)
attributes |= WNOHANG;
@@ -2459,7 +2643,7 @@
/* Disable job control signals for shell (parent) and
* for initial child code after fork */
- set_jobctrl_sighandler(SIG_IGN);
+//// set_jobctrl_sighandler(SIG_IGN);
/* Going to fork a child per each pipe member */
pi->alive_cmds = 0;
@@ -2486,9 +2670,9 @@
command->pid = BB_MMU ? fork() : vfork();
if (!command->pid) { /* child */
- if (ENABLE_HUSH_JOB)
- die_sleep = 0; /* let nofork's xfuncs die */
#if ENABLE_HUSH_JOB
+ die_sleep = 0; /* let nofork's xfuncs die */
+
/* Every child adds itself to new process group
* with pgid == pid_of_first_child_in_pipe */
if (G.run_list_level == 1 && G.interactive_fd) {
@@ -2514,9 +2698,9 @@
setup_redirects(command, NULL);
/* Restore default handlers just prior to exec */
- set_jobctrl_sighandler(SIG_DFL);
- set_misc_sighandler(SIG_DFL);
- signal(SIGCHLD, SIG_DFL);
+//// set_jobctrl_sighandler(SIG_DFL);
+//// set_misc_sighandler(SIG_DFL);
+//// signal(SIGCHLD, SIG_DFL);
/* Stores to nommu_save list of env vars putenv'ed
* (NOMMU, on MMU we don't need that) */
/* cast away volatility... */
@@ -2693,6 +2877,8 @@
* in order to return, no direct "return" statements please.
* This helps to ensure that no memory is leaked. */
+//TODO: needs re-thinking
+
#if ENABLE_HUSH_JOB
/* Example of nested list: "while true; do { sleep 1 | exit 2; } done".
* We are saving state before entering outermost list ("while...done")
@@ -2713,27 +2899,27 @@
restore_nofork_data(&G.nofork_save);
}
#endif
- if (G.ctrl_z_flag) {
- /* ctrl-Z has forked and stored pid of the child in pi->pid.
- * Remember this child as background job */
- insert_bg_job(pi);
- } else {
+//// if (G.ctrl_z_flag) {
+//// /* ctrl-Z has forked and stored pid of the child in pi->pid.
+//// * Remember this child as background job */
+//// insert_bg_job(pi);
+//// } else {
/* ctrl-C. We just stop doing whatever we were doing */
bb_putchar('\n');
- }
+//// }
USE_HUSH_LOOPS(loop_top = NULL;)
USE_HUSH_LOOPS(G.depth_of_loop = 0;)
rcode = 0;
goto ret;
}
- /* ctrl-Z handler will store pid etc in pi */
- G.toplevel_list = pi;
- G.ctrl_z_flag = 0;
-#if ENABLE_FEATURE_SH_STANDALONE
- G.nofork_save.saved = 0; /* in case we will run a nofork later */
-#endif
- signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
- signal(SIGINT, handler_ctrl_c);
+//// /* ctrl-Z handler will store pid etc in pi */
+//// G.toplevel_list = pi;
+//// G.ctrl_z_flag = 0;
+////#if ENABLE_FEATURE_SH_STANDALONE
+//// G.nofork_save.saved = 0; /* in case we will run a nofork later */
+////#endif
+//// signal_SA_RESTART_empty_mask(SIGTSTP, handler_ctrl_z);
+//// signal(SIGINT, handler_ctrl_c);
}
#endif /* JOB */
@@ -2854,11 +3040,17 @@
continue; /* not matched yet, skip this pipe */
}
#endif
- if (pi->num_cmds == 0)
- goto check_jobs_and_continue;
+ /* Just pressing <enter> in shell should check for jobs.
+ * OTOH, in non-interactive shell this is useless
+ * and only leads to extra job checks */
+ if (pi->num_cmds == 0) {
+ if (G.interactive_fd)
+ goto check_jobs_and_continue;
+ continue;
+ }
/* After analyzing all keywords and conditions, we decided
- * to execute this pipe. NB: has to do checkjobs(NULL)
+ * to execute this pipe. NB: have to do checkjobs(NULL)
* after run_pipe() to collect any background children,
* even if list execution is to be stopped. */
debug_printf_exec(": run_pipe with %d members\n", pi->num_cmds);
@@ -2871,6 +3063,7 @@
if (r != -1) {
/* we only ran a builtin: rcode is already known
* and we don't need to wait for anything. */
+ check_and_run_traps();
#if ENABLE_HUSH_LOOPS
/* was it "break" or "continue"? */
if (G.flag_break_continue) {
@@ -2895,6 +3088,7 @@
/* even bash 3.2 doesn't do that well with nested bg:
* try "{ { sleep 10; echo DEEP; } & echo HERE; } &".
* I'm NOT treating inner &'s as jobs */
+ check_and_run_traps();
#if ENABLE_HUSH_JOB
if (G.run_list_level == 1)
insert_bg_job(pi);
@@ -2905,11 +3099,13 @@
if (G.run_list_level == 1 && G.interactive_fd) {
/* waits for completion, then fg's main shell */
rcode = checkjobs_and_fg_shell(pi);
+ check_and_run_traps();
debug_printf_exec(": checkjobs_and_fg_shell returned %d\n", rcode);
} else
#endif
{ /* this one just waits for completion */
rcode = checkjobs(pi);
+ check_and_run_traps();
debug_printf_exec(": checkjobs returned %d\n", rcode);
}
}
@@ -2948,17 +3144,18 @@
} /* for (pi) */
#if ENABLE_HUSH_JOB
- if (G.ctrl_z_flag) {
- /* ctrl-Z forked somewhere in the past, we are the child,
- * and now we completed running the list. Exit. */
-//TODO: _exit?
- exit(rcode);
- }
+//// if (G.ctrl_z_flag) {
+//// /* ctrl-Z forked somewhere in the past, we are the child,
+//// * and now we completed running the list. Exit. */
+//////TODO: _exit?
+//// exit(rcode);
+//// }
ret:
- if (!--G.run_list_level && G.interactive_fd) {
- signal(SIGTSTP, SIG_IGN);
- signal(SIGINT, SIG_IGN);
- }
+ G.run_list_level--;
+//// if (!G.run_list_level && G.interactive_fd) {
+//// signal(SIGTSTP, SIG_IGN);
+//// signal(SIGINT, SIG_IGN);
+//// }
#endif
debug_printf_exec("run_list lvl %d return %d\n", G.run_list_level + 1, rcode);
#if ENABLE_HUSH_LOOPS
@@ -3478,10 +3675,10 @@
/* Process substitution is not considered to be usual
* 'command execution'.
* SUSv3 says ctrl-Z should be ignored, ctrl-C should not. */
- /* Not needed, we are relying on it being disabled
- * everywhere outside actual command execution. */
- /*set_jobctrl_sighandler(SIG_IGN);*/
- set_misc_sighandler(SIG_DFL);
+//// /* Not needed, we are relying on it being disabled
+//// * everywhere outside actual command execution. */
+ IGN_jobctrl_signals();
+//// set_misc_sighandler(SIG_DFL);
/* Freeing 'head' here would break NOMMU. */
_exit(run_list(head));
}
@@ -4287,7 +4484,6 @@
pid_t shell_pgrp;
shell_pgrp = getpgrp();
- close_on_exec_on(G.interactive_fd);
/* If we were ran as 'hush &',
* sleep until we are in the foreground. */
@@ -4298,8 +4494,8 @@
}
/* Ignore job-control and misc signals. */
- set_jobctrl_sighandler(SIG_IGN);
- set_misc_sighandler(SIG_IGN);
+//// set_jobctrl_sighandler(SIG_IGN);
+//// set_misc_sighandler(SIG_IGN);
//huh? signal(SIGCHLD, SIG_IGN);
/* We _must_ restore tty pgrp on fatal signals */
@@ -4312,6 +4508,16 @@
}
#endif
+static int set_mode(const char cstate, const char mode)
+{
+ int state = (cstate == '-' ? 1 : 0);
+ switch (mode) {
+ case 'n': G.fake_mode = state; break;
+ case 'x': /*G.debug_mode = state;*/ break;
+ default: return EXIT_FAILURE;
+ }
+ return EXIT_SUCCESS;
+}
int hush_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int hush_main(int argc, char **argv)
@@ -4408,7 +4614,7 @@
break;
case 'n':
case 'x':
- if (!builtin_set_mode('-', opt))
+ if (!set_mode('-', opt))
break;
default:
#ifndef BB_VER
@@ -4447,6 +4653,7 @@
// to (inadvertently) close/redirect it
}
}
+ init_signal_mask();
debug_printf("G.interactive_fd=%d\n", G.interactive_fd);
if (G.interactive_fd) {
fcntl(G.interactive_fd, F_SETFD, FD_CLOEXEC);
@@ -4475,9 +4682,10 @@
}
if (G.interactive_fd) {
fcntl(G.interactive_fd, F_SETFD, FD_CLOEXEC);
- set_misc_sighandler(SIG_IGN);
+//// set_misc_sighandler(SIG_IGN);
}
}
+ init_signal_mask();
#endif
#if ENABLE_HUSH_INTERACTIVE && !ENABLE_FEATURE_SH_EXTRA_QUIET
@@ -4530,93 +4738,63 @@
/*
* Built-ins
*/
-/* http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#trap
- *
- * Traps are also evaluated immediately instead of being delayed properly:
- * http://www.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_11
- * Example: hush -c 'trap "echo hi" 31; sleep 10; echo moo' & sleep 1; kill -31 $!
- * "hi" should not be displayed until the sleep finishes
- * This will have to get fixed ...
- */
-static void handle_trap(int sig)
-{
- int save_errno, save_rcode;
- char *argv[] = { NULL, G.traps[sig].cmd, NULL };
- /* Race! We transitioned from handled to ignore/default, but
- * the signal came in after updating .cmd but before we could
- * register the new signal handler.
- */
- if (!argv[1] || argv[1][0] == '\0')
- return;
- /* need to save/restore errno/$? across traps */
- save_errno = errno;
- save_rcode = G.last_return_code;
- builtin_eval(argv);
- errno = save_errno;
- G.last_return_code = save_rcode;
-}
static int builtin_trap(char **argv)
{
- size_t i;
+ int i;
int sig;
- bool ign = false;
- char *new_cmd = NULL;
+ char *new_cmd;
if (!G.traps)
- G.traps = xzalloc(sizeof(*G.traps) * NSIG);
+ G.traps = xzalloc(sizeof(G.traps[0]) * NSIG);
if (!argv[1]) {
/* No args: print all trapped. This isn't 100% correct as we should
* be escaping the cmd so that it can be pasted back in ...
*/
for (i = 0; i < NSIG; ++i)
- if (G.traps[i].cmd)
- printf("trap -- '%s' %s\n", G.traps[i].cmd, get_signame(i));
+ if (G.traps[i])
+ printf("trap -- '%s' %s\n", G.traps[i], get_signame(i));
return EXIT_SUCCESS;
}
- /* first arg is decimal: reset all specified */
- sig = bb_strtou(argv[1], NULL, 10);
+ new_cmd = NULL;
+ i = 0;
+ /* if first arg is decimal: reset all specified */
+ sig = bb_strtou(*++argv, NULL, 10);
if (errno == 0) {
int ret;
- i = 0;
set_all:
ret = EXIT_SUCCESS;
- while (argv[++i]) {
- char *old_cmd;
-
- sig = get_signum(argv[i]);
+ while (*argv) {
+ sig = get_signum(*argv++);
if (sig < 0 || sig >= NSIG) {
ret = EXIT_FAILURE;
+ /* mimic bash message exactly */
bb_perror_msg("trap: %s: invalid signal specification", argv[i]);
continue;
}
- /* Make sure .cmd is always a valid command list since
- * signals can occur at any time ...
- */
- old_cmd = G.traps[sig].cmd;
- G.traps[sig].cmd = xstrdup(new_cmd);
- free(old_cmd);
+ free(G.traps[sig]);
+ G.traps[sig] = xstrdup(new_cmd);
- debug_printf("trap: setting SIG%s (%i) to: %s",
- get_signame(sig), sig, G.traps[sig].cmd);
+ debug_printf("trap: setting SIG%s (%i) to '%s'",
+ get_signame(sig), sig, G.traps[sig]);
/* There is no signal for 0 (EXIT) */
if (sig == 0)
continue;
if (new_cmd) {
- /* add/update a handler */
- struct sigaction act = {
- .sa_handler = ign ? SIG_IGN : handle_trap,
- .sa_flags = SA_RESTART,
- };
- sigemptyset(&act.sa_mask);
- sigaction(sig, &act, old_cmd ? NULL : &G.traps[sig].oact);
- } else if (old_cmd && !new_cmd)
- /* there was a handler, and we are removing it */
- sigaction_set(sig, &G.traps[sig].oact);
+ sigaddset(&G.blocked_set, sig);
+ } else {
+ /* there was a trap handler, we are removing it
+ * (if sig has non-DFL handling,
+ * we don't need to do anything) */
+ if (sig < 32 && (G.non_DFL_mask & (1 << sig)))
+ continue;
+ sigdelset(&G.blocked_set, sig);
+ }
+ sigprocmask(SIG_SETMASK, &G.blocked_set, NULL);
}
return ret;
}
@@ -4624,17 +4802,15 @@
/* first arg is "-": reset all specified to default */
/* first arg is "": ignore all specified */
/* everything else: execute first arg upon signal */
- if (!argv[2]) {
+ if (!argv[1]) {
bb_error_msg("trap: invalid arguments");
return EXIT_FAILURE;
}
- if (LONE_DASH(argv[1]))
+ if (LONE_DASH(*argv))
/* nothing! */;
else
- new_cmd = argv[1];
- if (argv[1][0] == '\0')
- ign = true;
- i = 1;
+ new_cmd = *argv;
+ argv++;
goto set_all;
}
@@ -4891,16 +5067,6 @@
*
* So far, we only support "set -- [argument...]" and some of the short names.
*/
-static int builtin_set_mode(const char cstate, const char mode)
-{
- int state = (cstate == '-' ? 1 : 0);
- switch (mode) {
- case 'n': G.fake_mode = state; break;
- case 'x': /*G.debug_mode = state;*/ break;
- default: return EXIT_FAILURE;
- }
- return EXIT_SUCCESS;
-}
static int builtin_set(char **argv)
{
int n;
@@ -4922,7 +5088,7 @@
if (arg[0] == '+' || arg[0] == '-') {
for (n = 1; arg[n]; ++n)
- if (builtin_set_mode(arg[0], arg[n]))
+ if (set_mode(arg[0], arg[n]))
goto error;
continue;
}
@@ -5068,27 +5234,29 @@
int ret = EXIT_SUCCESS;
int status;
- if (argv[1] == NULL)
+ if (*++argv == NULL)
/* don't care about exit status */
- wait(&status);
+ wait(NULL);
- while (argv[1]) {
- pid_t pid = bb_strtou(argv[1], NULL, 10);
+ while (*argv) {
+ pid_t pid = bb_strtou(*argv, NULL, 10);
if (errno) {
- bb_perror_msg("wait %s", argv[1]);
+ /* mimic bash message */
+ bb_error_msg("wait: '%s': not a pid or valid job spec", *argv);
return EXIT_FAILURE;
- } else if (waitpid(pid, &status, 0) == pid) {
+ }
+ if (waitpid(pid, &status, 0) == pid) {
if (WIFSIGNALED(status))
ret = 128 + WTERMSIG(status);
else if (WIFEXITED(status))
ret = WEXITSTATUS(status);
- else
+ else /* wtf? */
ret = EXIT_FAILURE;
} else {
- bb_perror_msg("wait %s", argv[1]);
+ bb_perror_msg("wait %s", *argv);
ret = 127;
}
- ++argv;
+ argv++;
}
return ret;